Industrial plants have numerous machines that perform various tasks. These machines transfer status data to a central information system. The central information system correlates this status data to time and stores the correlated status/time data for each machine. Thus, the central information system can track the status of individual machines or aggregate data from several machines to track status at the plant level.
An operator uses an operator interface terminal to control an individual machine. The operator provides control inputs to the operator interface terminal, and the operator interface terminal processes the control inputs to transfer a corresponding control signal to the machine. The machine operates in response to the control signal. The operator interface terminal also receives status data from the machine. The operator interface terminal correlates the machine status data to time and internally stores the correlated status/time data. The operator interface terminal displays the correlated status/time data to the operator. If desired, the operator may manually retrieve the correlated status/time data from the operator interface terminal for manual transfer to the central information system.
Unfortunately, the status data that is stored in the central system may be correlated to different time points than the status data that is stored in the operator interface terminal. This time discontinuity may cause problems when comparing the status data from the operator interface terminal to the status data stored in the central information system.